Fix various invalid memory access problems with _e_editable_text_insert
Fix various invalid memory access problems with _e_editable_text_insert

Patch by Helder Ribeiro:

   Hi people,

   I found a couple errors in the function _e_editable_text_insert.

   - when copying from the old string (n bytes) to the new one (m > n
   bytes) it was writing garbage into the new one (copying m bytes from
   old);
   - when memsetting the old string with 0's (part of extra security
   measure for password entry) it was writing m 0's into old, therefore
   writing past old's boundary, into unreserved memory;
   - a couple checks for NULL were missing.




git-svn-id: 6ac5796aeae0cef97fb47bcc287d4ce899c6fa6e@35911 7cbeb6ba-43b4-40fd-8cce-4c39aea84d33

jordemort/e17,jordemort/e17,jordemort/e17